[IMP] purchase: replace vendor bills screenshots

[brse-odoo]

This PR is an [IMP] to the manage doc in Odoo's Purchase documentation, specific to 17.0.

Here's what I did:

• Replaced all screenshots for 17.0 UI, removed some screenshots no longer relevant

Note: This PR was only to update small instructions and replace screenshots. A second, targeted PR for a more robust rewrite will follow once this is merged.

Project Task Link

[robodoo]

Pull request status dashboard.

[brse-odoo]

Hi @Felicious Real quick PR ready for you to review - just replaced the screenshots on this one. Thank you!

[brse-odoo]

@odoo/us-doc-review Real quick PR ready for review - just replaced the screenshots on this one. Thank you!

[brse-odoo]

@samueljlieber Real quick PR ready for review - just replaced the screenshots on this one. Thank you!